As is well known in the art, vibratory processing equipment has been developed to satisfy a wide range of diverse applications. It is oftentimes the case that a system for handling any of a variety of different materials will include as an integral component an exciter for generating vibration. Generally, the exciter is used in a variety of applications, typically to transport a material to and through a processing section to a post-processing section, such as in a vibratory conveyor for transporting materials along a generally horizontal path, or in a spiral elevator for vertically transporting materials.
Exciters used in vibratory apparatus typically include a frame resiliently connected to a conveyor or other structure which carries the process material. At least one, and typically two, rotatable shafts are supported on the frame. Each shaft carries an eccentric weight which creates a vibrational force as it rotates with the shaft. A motor is provided to drive the driven shaft. The motor has a motor shaft, and a drive belt is entrained about the motor shaft and the driven shaft. Accordingly, rotation of the motor shaft moves the drive belt which, in turn, causes the driven shaft to rotate. The rotating eccentric weight attached to the driven shaft creates the vibrational force which is imparted to the exciter flame. Vibration of the exciter is transferred, such as by reactor springs, to the conveyor or other structure to effect the desired vibrational process.
During operation, it will be appreciated that the exciter may move in several directions. In vibratory apparatus used to produce a vertical vibration, for example, the exciter may vibrate or oscillate in different directions during startup, normal operation, and shutdown of the exciter. During startup, the driven shafts are initially at rest as the motor begins to rotate the shaft. Until the driven shafts reach normal operating speed, rotation of the eccentric weights may not be synchronized or may otherwise result in primarily horizontal movement of the exciter. During normal operation, the exciter oscillates in a generally vertical direction to impart the desired vibrational force. During shut down, the eccentric weights again may become out of synchronization, creating primarily horizontal movement of the exciter.
The varying movement of the exciter makes it difficult to reliably couple a motor to each driven shaft. Currently, each motor is typically fixed to a stationary support, such as a base frame or the ground. As a result, movement of the exciter varies the distance between each motor shaft and respective driven shaft, so that the tension in the drive belt is also varied. The varying tension causes the belt to slip during operation, and often creates excessive wear on the belt, leading to premature belt failure.
Another type of motor base for vibratory apparatus, marketed as the "TENS-A-MATIC" pivoted motor base by Murray Equipment Co., Inc. located in Detroit, Mich., provides a base which allows the motor to pivot with respect to the driven shaft. The base includes a pair of arms which is supported for pivoting about a pivot axis. The motor is positioned on the arms such that an increase in motor load (e.g. starting load) creates a reaction torque which pushes down on the arms. The pivot axis is located below the arms such that downward movement of the arms increases the distance between the motor shaft and the driven shaft. When the motor load returns to normal (e.g., motor reaches fill speed), the reaction torque dissipates and the arms swing upward, decreasing the distance between the motor shaft and the driven shaft. To compensate for overly heavy motor loads, a spring may be attached to the arms below the motor which prevents the arms from pivoting too far. The pivot motor base allows the distance between the motor shaft and driven shaft to vary according to motor load, and therefore the drive belt is still subject to wear, as detailed above.
The present invention is directed to overcoming one or more of the foregoing problems while achieving one or more of the resulting objects by providing a unique motor base for vibratory apparatus.